Electric underground conduit



` (No Model.)

D. 0. PAIGE.

ELECTRIC UNDERGROUND GONDUIT.

No. 394,207.l Patented Deo. 1l, 1888.

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UNITED STATES PATENT ELECTRlC UNDERGROUND CONDUlT.

SPECIFICATION forming part of Letters Patent No. 394,207, dated December 1l, 1888.

Application filed March 2l, 1888.

To @ZZ whom it may con/c0771.:

Be it known that I, DAvID O. PAIGE, a citizen of the United States, residing at Detroit, county of Vayne, State of Michigan, have invented a certain neyv and useful Improvement in Electric Underground Conductors; and I declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying' drawings, which form a part of this specification.

In the drawings, Figure l a longitudinal section of a lead pipe and its joint embodying my invention. Fig. 2 is a similar section of an iron pipe With its joint embodying my invention. Fig. 3 represents several wires located in the same tube.

The purpose of my invention is the production of an insulated electric conducting-wire suitable for use in the umlergrounding ot' electric-light Wires and in other localities Where electric Wires are required to be perfectly insulated.

My invention consists, essentially, in arranging the said wires Within a lead, iron, or other pipe, said ivire or Wires each embedded in and thoroughly surrounded with a plastic composed of silicious material, which upon the application of heat will become vitreous, and will thoroughly and permanently support and insulate the said conductor or conductors.

In carrying out my invention, A represents a pipe, of lead, iron, or other suitable material.

B is'an interior comlucting-yvire.

C is the vitreous insulating` material which fills the space between the Wire and the pipe.

This conductor is made as follows: I make a dough composed of a mixture of silicate of soda, With silex, sand, crushed quartz, crushed glass, or other similar silicious substance, these all mixed with ivater to the consistency of a dough and applied as a coating to the Wire or nires to be insulated, yvhich Wire or Wires are introduced Within the pipe A. Heat is then applied to the pipe, and in applying the heat I prefer to begin at the middle and cause the heat to approach therefrom toward the ends, in order to drive out such vapor as may be generated by the operation from the ends of the pipe. The heat thus applied is Serial No. 268,003. (No model.)

carried to the point necessary for fusing' the silicious substance into a vitreous mass. This is accomplished at a temperature considerably below the melting-point of lead, and can therefore be accomplished in a lead pipe as well as in a pipe of iron or other more refractory material. The result of this heat is to create a very hard spongy insulating mass of vitreous matter in the nature of glass. If the quantity of dough is small as compared with the interior of the pipe, the mass will be more spon gy but if the mass of dough nearly iills the pipe the mass will be more dense and less spongy. The heat need be carried only to such a degree as to produce sufficient vitritication to solidify the mass Without beingl carried to the extent of reducing it to the form of a molten glass. A conductor insulated in this ivay is thoroughly protected against liability ot' being subsequently brought into contact yvith the surface of the pipe, for the mass cannot, under any possible conditions which it Would be subjected to, be softened or caused to run. It is, moreover, much better protected than conductors surrounded by rubber or cotton fiber or petroleum compounds of any nature, for all such substances are by continued use improved in their conducting qualities, and to that extent their insulating' qualities are impaired, so that what was for a period a good insulator eventually becomes a conductor, and so serves to seep off the cm'rent and eventually form a connection from the Wire to the pipe, and thence, of course, to the ground.

It is especially' true of such conductors that the application of heat-such as might be induced by a bad section of wire or a poor joint-Will quickly soften and destroy the insulation or convert it into carbon or other conductor. YVith my insulation, however, heat can in no Way impair its conducting quality; in fact a great heat would simply reduce it at that particular point to a more perfect glass, and consequently to the condition of a more perfect insulator, Which would at once seal up the passage through yvhich moisture might have gained access to the Wire, and would house in and render harmless any remnant of moisture which might remain next to the yvire.

The process for connecting the ivires and locating them Within the pipes prior to heat- IOO ing may be effected in a variety of ways. Thus, for instance, the wire or wires might be drawn through suitable guides, while the dough is simultaneously squeezed through a surrounding die in the same way that tile is made. This might be easily inserted in the tube by simply wetting the dough, so as to `make its surface slippery, which would enable it to be drawn easily through the tube; or the dough, with its wires, might be squeezed directly through the tube from a die, as above explained Vhere the pipe that is employed is of lead, I prefer to make the joints as shown in Fig. l. To this end I would tin the projecting ends h of the wires and would incase them at this point with a thin copper tube, D, and would then solder them together, after which I would apply a collar, E, of lead over the junction of the pipes and finish the same with a wipejoint, d.

If the tube A were of iron, I would imite the ends of the wires in the same manner as above explained, and would then apply a union, F, in the same way that iron pipes are usually united. The wires thus insulated might be single, or the same pipe might contain several Wires. The conductors thus insulated may be either laid directly in the ground without any other protection, or may be laid in protecting-conduits.

The joint-piece F may, if desired, be perforated at f to facilitate filling' in about the joint a filling, f of insulating compound. This may or may not be employed.

That I claim isl. An insulated electrical conductor consisting of the combination, with a wire and a surrounding metallic pipe, of an intermediate insulating material formed of silicate of soda, with silex, crushed quartz, crushed glass, or other similar silicious matter, the same being subsequently vitried and reduced to the form of a hard spongy vitreous mass by heat, substantially as described.

2. The combination, with an electric-light wire and incasing metallic pipe, of a hard.

spongy vitreous insulating material, iilling the space between the wire and pipe, said vitreous substance composed of silicate of soda and silex, crushed quartz, crushed glass, or other similar silicious materials mixed, with water to a dough and vitritied about the wire in the pipe by heat, substantially as and for the purposes described,

The combination, with an electric wire, of an incasing lead pipe and a Yitriiied insulating mass iilling the space between the conductor and the pipe, said mass introduced in the form of a dough composed of silicate of soda, with silex, crushed quartz, crushed glass, or other similar silicious material7 mixed to a dough with water an d vitriticd within the pipe by heat, substantially7 as and t'or the purposes described.

In testimony whereof I sign this specification in the presence of two witnesses.

j DAVID O. PAIGE. .Vitnesses:

M. B. ODOGHERTY, A. E. MANSFIELD. 

